The tide rose in Martinez and a couple of low-lying areas are showing the effects.
A section of Waterfront Road about a mile east of Interstate 680 was flooded Thursday as water from the nearby marshes flowed over the asphalt.
Cars and trucks were still able to drive through the water as of midday Thursday.
Martinez Police Sgt. David Mathers said the marina parking had minor flooding as of midday Thursday. The water level near the bait shop and Yacht Club is also rising.
"This is the highest level I've ever seen and I've been here 10 years," said Mathers.
The flooding inundated on a sunny day. It's caused by a phenomena known as the "King Tide." It is affecting coastlines all along California Thursday and Friday.